Page 117 of 557

6-66 ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10)
INSPECTION
STEPACTIONYESNO
1Was “ENGINE DIAG. FLOW TABLE” performed?Go to Step 2.Go to “ENGINE
DIAG. FLOW
TABLE”.
2Is there DTC(s) other than fuel system
(DTC P0171 / P0172)?Go to applicable
DTC Diag. Flow
Table.Go to Step 3.
3Check HO2S-1 Output Voltage.
1) Connect scan tool to DLC with ignition switch OFF.
2) Warm up engine to normal operating temperature and keep
it at 2000 r / min. for 60 sec.
3) Repeat racing engine (Repeat depressing accelerator pedal
5 to 6 times continuously and take foot off from pedal to
enrich and enlean A / F mixture). See Fig. 1.
Does HO2S-1 output voltage deflect between below 0.3 V and
over 0.6 V repeatedly?Go to Step 4.Go to DTC
P0130 Diag.
Flow Table
(HO2S-1 circuit
check).
4Check Fuel Pressure (Refer to section 6E1 for details).
1) Release fuel pressure from fuel feed line.
2) Install fuel pressure gauge.
3) Check fuel pressure. See Fig. 2.
With fuel pump operating
and engine at stop : 160 – 210 kPa, 1.6 – 2.1 kg / cm
2,
22.7 – 29.9 psi.
At specified idle speed : 90 – 140 kPa, 0.9 – 1.4 kg / cm
2,
12.8 – 20.0 psi.
Is measured value as specified?
Go to Step 5.Go to Diag. Flow
Table B-3 Fuel
Pressure Check.
5Check Fuel Injectors and Circuit.
1) Turn ignition switch OFF and disconnect fuel injector
connector.
2) Check for proper connection to fuel injector at each terminals.
3) If OK, then check injector resistance. See Fig. 3.
Injector resistance: 0.5 – 1.5 Ω at 20C (68F)Go to Step 6.Check injector
circuit or replace
fuel injector.
4) Connect injector, connector.
5) Check that fuel is injected out in conical shape from fuel
injector when running engine.
6) Check injector for fuel leakage after engine stop.
Fuel leakage: Less than 1 drop / min.
Is check result satisfactory?
6Check EVAP Canister Purge Valve.
1) Disconnect purge hose (1) from EVAP canister.
2) Place finger against the end of disconnected hose.
3) Check that vacuum is not felt there when engine is cool and
running at idle. See Fig. 4.
Is vacuum felt?Check EVAP
control system
(See Section
6E1).Go to Step 7.
7Check intake manifold absolute pressure sensor for
performance (See DTC P0105 Diag. Flow Table).
Is it in good condition?Go to Step 8.Repair or
replace.
Page 119 of 557

Ignition coil
Igniter
Ignition switch
Main
fuse
Injector resistor
Fuel injector
Crankshaft
position sensor
Camshaft
position sensor
Ground
at engine “I / G COIL METER”
Main relay
6-68 ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10)
DTC P0300 RANDOM MISFIRE DETECTED (Misfire detected at 2 or more
cylinders)
DTC P0301 CYLINDER 1 MISFIRE DETECTED
DTC P0302 CYLINDER 2 MISFIRE DETECTED
DTC P0303 CYLINDER 3 MISFIRE DETECTED
CIRCUIT DESCRIPTION
ECM (PCM) monitors crankshaft revolution speed and engine speed via the crankshaft position sensor and cylin-
der No. via the camshaft position sensor. Then it calculates the change in the crankshaft revolution speed and from
how many times such change occurred in every 200 or 1000 engine revolutions, it detects occurrence of misfire.
When ECM (PCM) detects a misfire (misfire rate per 200 revolutions) which can cause overheat and damage to
the three way catalytic converter, it makes the malfunction indicator lamp (MIL) flash as long as misfire occurs at
that rate.
After that, however, when the misfire rate drops, MIL remains ON until it has been judged as normal 3 times under
the same driving conditions.
Also, when ECM (PCM) detects a misfire (misfire rate per 1000 revolutions) which will not cause damage to three
way catalytic converter but can cause exhaust emission to be deteriorated, it makes MIL light according to the 2
driving cycle detection logic.
Page 120 of 557

ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10) 6-69
Below
specified value DTC DETECTING CONDITION
POSSIBLE CAUSE
Engine under other than high revolution condition
Not on rough road
Engine speed changing rate
Manifold absolute
pressure changing rate
Throttle opening changing rate
Misfire rate per 200 or 1000 engine revolutions (how
much and how often crankshaft revolution speed
changes) is higher than specified valueEngine overheating
Vacuum leaks (air inhaling) from air intake system
Ignition system malfunction (spark plug(s), high-
tension cord(s), ignition coil assembly)
Fuel pressure out of specification
Fuel injector malfunction (clogged or leakage)
Engine compression out of specification
Valve lash (clearance) out of specification
Manifold absolute pressure sensor malfunction
Engine coolant temp. sensor malfunction
PCV valve malfunction
EVAP control system malfunction
DTC CONFIRMATION PROCEDURE
WARNING:
When performing a road test, select a place where there is no traffic or possibility of a traffic accident
and be very careful during testing to avoid occurrence of an accident.
Road test should be carried out with 2 persons, a driver and a tester.
1) Turn ignition switch OFF.
2) Clear DTC with ignition switch ON.
3) Check vehicle and environmental condition for:
–Altitude (barometric pressure): 2400 m, 8000 ft or less (560 mmHg, 75 kPa or more)
–Ambient temp.: –10C, 14F or higher
–Intake air temp.: 70C, 158F or lower
–Engine coolant temp.: –10 – 11 0C, 14 – 230F
4) Start engine and keep it at idle for 2 min. or more.
5) Check DTC in “DTC” mode and pending DTC in “ON BOARD TEST” or “PENDING DTC” mode.
6) If DTC is not detected at idle, consult usual driving based on information obtained in “Customer complaint analy-
sis” and “Freeze frame data check”.
Page 121 of 557

6-70 ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10)
INSPECTION
STEPACTIONYESNO
1Was “ENGINE DIAG. FLOW TABLE” performed?Go to Step 2.Go to “ENGINE
DIAG. FLOW
TABLE“.
2Is there DTC other than Fuel system (DTC P0171 / P0172)
and misfire (DTC P0300-P0303)?Go to applicable
DTC Diag.
Flow Table.Go to Step 3.
3Check Ignition System.
1) Remove spark plugs and check them for;
Air gap: 1.0 – 1.1 mm (0.040 – 0.043 in.) See Fig. 1.
Carbon deposits
Insulator damage
Plug type
If abnormality is found, adjust, clean or replace.
2) Disconnect injector connector. See Fig. 2.
3) Connect spark plugs to high tension cords and then
ground spark plugs.
4) Crank engine and check that each spark plug sparks.
Are above check results satisfactory?Go to Step 4.Check ignition
system parts
(Refer to Section
6F).
4Check Fuel Pressure (Refer to Section 6E1 for details).
1) Release fuel pressure from fuel feed line.
2) Install fuel pressure gauge. See Fig. 3.
3) Check fuel pressure.
With fuel pump operating
and engine at stop : 160 – 210 kPa, 1.6 – 2.1 kg / cm
2,
22.7 – 29.9 psi.
At specified idle speed : 90 – 140 kPa, 0.9 – 1.4 kg / cm
2,
12.8 – 20.0 psi.
Is measured value as specified?
Go to Step 5.Go to Diag. Flow
Table B-3 fuel
pressure check.
5Check Fuel Injector and Circuit.
1) Turn ignition switch OFF and disconnect fuel injector
connector.
2) Check for proper connection to fuel injector at each terminal.
3) If OK, then check injector resistance. See Fig. 4.
Injector resistance: 0.5 – 1.5 Ω at 20C (68F).
4) Connect injector connector.
5) Check that fuel is injected out in conical shape from fuel
injector when running engine.
6) Check injector for fuel leakage after engine stop.
Fuel leakage: Less than 1 drop / min.
Is check result satisfactory?Go to Step 6.Check injector
circuit or replace
fuel injector.
Page 122 of 557

ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10) 6-71
1. Throttle body
2. Fuel feed hose
GoodNo good1. Injector connector
STEPACTIONYESNO
6Check PCV valve for clogging (See Section 6E1).
Is it in good condition?Go to Step 7.Replace PCV valve.
7Check EVAP Canister Purge Valve for Closing.
1) Disconnect purge hose (1) from EVAP canister.
2) Place finger against the end of disconnected hose.
3) Check that vacuum is not felt there, when engine is
cool and running at idle. See Fig. 5.
Is vacuum felt?Check EVAP
control system
(See Section 6E1).Go to Step 8.
8Check intake manifold pressure sensor for performance
(See Section 6E1).
Is it in good condition?Go to Step 9.Repair or replace.
9Check engine coolant temp. sensor for performance
(See Section 6E1).
Is it in good condition?Go to Step 10.Replace engine
coolant temp.
sensor.
10Check parts or system which can cause engine rough
idle or poor performance.
–Engine compression (See Section 6A).
–Valve lash (See Section 6A).
–Valve timing (Timing belt installation. See Section 6A).
Are they in good condition?Check wire harness
and connection of
ECM (PCM) ground,
ignition system and
fuel injector for
intermittent open
and short.Repair or replace.
Fig. 1 for Step 3 Fig. 2 for Step 3 Fig. 3 for Step 4
Fig. 4 for Step 5 Fig. 5 for Step 7
Page 125 of 557
Display of fuel injection signal using oscilloscope
1. CMP sensor signal
2. Fuel injector signal
3. Fuel injection time
2V/Div.
20V/Div.1
2
10ms/Div
Waveforms at specified idle speed 3 Sensor rotor
in distributorCamshaft
position sensor
6-74 ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10)
DTC P0340 CAMSHAFT POSITION (CMP) SENSOR CIRCUIT MALFUNCTION
CIRCUIT DESCRIPTION
DTC DETECTING CONDITIONPOSSIBLE CAUSE
No CMP sensor signal for 2 seconds at engine
cranking (CKP sensor signal is inputted).CMP sensor circuit open or short.
Signal rotor teeth damaged.
CMP sensor malfunction, foreign material being
attached or improper installation.
ECM (PCM) malfunction.
Reference
Connect oscilloscope between terminals C01-2 and C01-10 of ECM (PCM) connector connected to ECM (PCM)
and check CMP sensor signal.
DTC CONFIRMATION PROCEDURE
1) Clear DTC.
2) Start engine and keep it at idle for 1 min.
3) Select “DTC” mode on scan tool and check DTC.
Page 147 of 557

“IG
COIL
METER”
Main
fuseIgnition
switch
Main
relayTo other circuits
Injector resistor Fuel injector
6-96 ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10)
TABLE B-1 FUEL INJECTOR CIRCUIT CHECK
INSPECTION
STEPACTIONYESNO
1Was “ENGINE DIAG. FLOW TABLE” performed?Go to Step 2.Go to “ENGINE DIAG.
FLOW TABLE”.
2Injector Circuit Check
1) Check injector circuit for short.
Is fuel injected from injector at ignition switch ON?“Y/B” wire shorted to
ground or faulty
injector.
If wire and injector is
as specified
respectively and then
substitute known-
good ECM (PCM) and
recheck.Go to Step 3.
3Injector Check
1) Check injector for fuel Injection referring to FUEL
INJECTOR ON-VEHICLE INSPECTION in
Section 6E1.
Is fuel injected from injector at engine cranking?Go to Step 4.Go to Step 5.
4Injector Leakage Check
1) Check injector for leaks referring to FUEL
INJECTOR ON-VEHICLE INSPECTION in
Section 6E1.
Is it in good condition?Injector and its circuit
are in good condition.Faulty fuel injector.
5Check Injector for Operating Sound.
1) Using sound scope, check injector for operating
sound at engine cranking.
Is it detected?Proceed to DIAG.
FLOW TABLE B-2 and
B-3.Go to Step 6.
Page 148 of 557
ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10) 6-97
STEPACTIONYESNO
6Check Injector Resistor for Resistance.
1) Disconnect resistor connector with ignition switch
OFF.
2) Check for proper connection to resistor at each
terminals.
3) If connection is OK, check resistance.
Is resistance 1.9 – 2.1 Ω (at 20C, 68F)?“W/Bl”, “Y/G” or “Y/B”
wire open or poor
C02-12 connection.
If wires and
connections are OK,
substitute a known-
good ECM (PCM) and
recheck.Replace resistor.